1. Field of the Invention
The present invention relates to a liquid crystal module, a method of driving the liquid crystal module, and a liquid crystal display.
2. Description of the Related Art
Generally, liquid crystal displays (“LCDs”) have superior characteristics, such as low-voltage driving, low power consumption, light weight, and slimness, and therefore they have been used as monitors of personal computers, or displays of TVs.
A transmissive-type liquid crystal display includes a backlight unit and a liquid crystal module arranged in a front side of the backlight unit. The backlight unit supplies light to a display panel of the liquid crystal module. The liquid crystal module uses a plurality of pixels to modulate the light supplied from the backlight unit and displays the modulated light as an image. The backlight unit has a reflection plate, a light source, and an optical sheet. In addition, the backlight unit applies a current to the light source, which thereby enables the light source to supply light to the display panel.
In a reflective-type liquid crystal display, a pixel electrode of a liquid crystal module includes a reflective metal component. Light incident onto the liquid crystal module from an exterior is modulated by a liquid crystal layer, reflected by the pixel electrode, and then output to the exterior. The reflective-type liquid crystal display may also include a side light unit, which supplies light from a side of the liquid crystal module.
Recently, in order to improve the display quality of liquid crystal displays, liquid crystal displays including a plurality of thin film transistors (“TFTs”) per pixel have been developed. For examples, see Japanese patent publication number 2005-140937, Japanese patent publication number 2005-326624, Japanese patent publication number 2002-296617, and Japanese patent publication number 2003-222902.
The liquid crystal module displays images by using a pixel TFT provided in one area of a pixel to supply a voltage to the liquid crystal of the liquid crystal module. Electric charges are charged into a storage capacitor, which is connected to a source electrode and a control electrode of the pixel TFT. An insulator or semiconductor is interposed between the source and control electrodes. A liquid crystal capacitor, which includes a pixel electrode, a common electrode and a liquid crystal layer is interposed between the pixel electrode and the common electrode. When the voltage supplied between the pixel electrode and the common electrode is varied an alignment state of liquid crystal may be changed. This change in the alignment state of the liquid crystal affects the transmittance of the pixel.
Liquid crystal displays may display moving images by rapidly displaying a series of slightly changing images. Each image is displayed for a time period called a frame.
In order to display an image, the liquid crystal module maintains the potential difference between the pixel electrode and the common electrode to control an alignment state of liquid crystal during one frame. However, a current path within the pixel TFT makes the potential of the pixel electrode difficult to be constantly maintained during the one frame. If the potential of the pixel electrode is not constantly maintained during the one frame, the alignment state of the liquid crystal is changed, so a desired image is not displayed during the entire length of the frame.